


Daddy's Boy

by omegadeanlovesalphacas



Category: Supernatural
Genre: Alpha Castiel (Supernatural), Alpha Castiel/Omega Dean Winchester, Alpha/Beta/Omega Dynamics, Alpha/Omega, Castration, Claiming, Collars, Daddy Kink, Dominance, Humiliation, Knotting, Leashes, M/M, Mpreg, Omega Dean, Omega Dean Winchester, Orgasm Control, Plugs, Public Punishment, Public Sex, Slut Shaming, Spanking
Language: English
Status: Completed
Published: 2017-05-14
Updated: 2017-05-14
Packaged: 2018-10-31 13:21:44
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,007
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10900203
Author URL: https://archiveofourown.org/users/omegadeanlovesalphacas/pseuds/omegadeanlovesalphacas
Summary: Dean wants to be Castiel’s omega. Trouble is, Dean is an alpha. But not for long.





	Daddy's Boy

**Author's Note:**

> This is an Alpha/omega kink prompt fill. Expect more porn than plot, and lots of power imbalance between Cas and Dean. Mind the warnings and kinks in the tags.
> 
> WARNING! This story contains castration as a kink! [Click here if you’re new to castration kink and want to read my write up explaining it.](http://omegadeanlovesalphacas.tumblr.com/castrationkink)

Dean and Castiel sat on the couch, both of them staring at the thick black collar that sat on the coffee table.

“Are you sure you want to do this?” Castiel asked, looking over at Dean.

Dean nodded, resolute. “Yes. All I’ve ever wanted was to have a family with you, and not just that, I want to carry your pups. This is the only way.”

“It won’t be easy,” Castiel said.

“I know,” Dean replied, taking a deep breath. But it was exciting, too.

Despite the fact that they were both alphas, Dean had always felt the instinct to submit to Cas. He was such a strong alpha, he’d easily dominated Dean from day one. But that had never meant more than Castiel’s knot in Dean’s ass, this was going to be a much deeper level of submission.

Because Dean wanted to be an omega. It was the only way they could start a family together, at least if they wanted biological children. And Dean desperately wanted to be able to give Cas children.

But converting an alpha to an omega was very difficult. Castiel would have to thoroughly dominate Dean in every way, for several months. The biological change took time, only after an extended period of deep submission would Dean’s body start to shift.

Dean would also have to be castrated. He wasn’t very excited about that, but he was willing to do it. It was the only way to get what he wanted.

“Please, Cas,” Dean begged, baring his neck in submission to the alpha. “Please collar me, I’m ready.”

Castiel took a deep breath, and the alpha couldn’t hide the scent of excitement. He was obviously going to enjoy this process. He picked up the collar and unbuckled it, wrapping it around Dean’s neck, then paused before he buckled it again.

“Say it,” he ordered, voice deep and powerful.

“I submit myself to you,” Dean said, the rehearsed words coming easily. “My mind, body, and soul belong to you from now on. I live only for your pleasure.”

“Good boy,” Castiel praised, buckling the collar snug around Dean’s neck. He beamed and pressed a kiss to Dean’s lips. “I love you.”

“I love you too, Cas,” Dean said, returning the smile.

Castiel let out a little growl and tugged on Dean’s collar. “Try that again.”

Dean blushed, remembering their agreement. “I love you too, Daddy,” he said, squirming a little in embarrassment. His stomach fluttered a little, nervous and excited for what was to come.

“That’s better,” Castiel said, smiling at him. “Now take off those clothes, you know you aren’t allowed to be wearing them.”

Dean bit his lip and nodded. “Yes, Daddy.” He quickly stood and stripped down, until he was standing in front of Castiel completely naked.

Castiel smiled and pulled his phone out of his pocket, then spread his legs open wide. “Be a good boy and warm Daddy’s cock while I call and schedule your castration,” he said, unzipping his slacks. “If you’re very good I’ll knot you when I’m done.”

Dean’s face burned but he was quick to comply. “Thank you, Daddy.” He said, getting down on his knees in front of his alpha.

“Try that again,” Castiel ordered, giving Dean a sharp look.

Dean whimpered a little in embarrassment, but he knew what Castiel wanted. “Thank you for your cock, Daddy,” he said, then pulled the alpha’s cock free of his pants and pulled it into his mouth.

Castiel smiled. “Good boy.”

* * *

That night after knotting Dean twice in a row, Castiel pushed a thick plug into Dean’s hole, keeping his seed safely inside. That was another important part of the transition.

Dean squirmed a little, surprised that he actually enjoyed the feeling. Castiel had never plugged him before.

“Get used to it, baby boy,” Castiel said with a grin. “Good little boys are always plugged up.”

Dean blushed and nodded. “Thanks, Daddy.”

* * *

It turned out that Castiel was able to get an appointment to have Dean castrated the very next day. The alpha wasn’t wasting any time.

“Come on,” Castiel said, putting on his shoes. Dean wasn’t allowed any, of course. “Fetch me your leash.”

“Yes, Daddy,” Dean said, getting the matching black leash from the hook by the front door and bringing it to Castiel. His stomach flipped when his alpha clipped it to the ring on his collar, tugging gently.

“One more thing,” Castiel said, pulling a thick black sharpie out of his pocket. He uncapped it and started to write across Dean’s chest in big letters.

It read _Bitch In Training._

Dean’s face burned and he gaped a little as Castiel wrote the same thing across his back. And yet some how his cock twitched in interest.

Castiel noticed and laughed. “My little boy likes being humiliated, don’t you?”

Dean whimpered, knowing he couldn’t do anything but answer honestly. “Yes, Daddy,” he mumbled.

“What was that?” Castiel demanded, yanking on Dean’s leash.

Dean gasped, speaking louder. “Yes, Daddy!”

Castiel smiled. “Good boy.” He picked up his keys and headed for the door, Dean in tow.

Driving in the car wasn’t so bad, but the short walk from the parking lot to the clinic was mortifying. The thick plug in Dean’s ass wiggled a little with each step, making his cock half hard from the stimulation.

An alpha was walking out the front doors of the clinic just as they were about to walk in. He smiled at Castiel and said, “That’s a nice looking bitch you have there.”

Dean glared at him. “Fuck off,” he snapped, entirely out of habit, completely forgetting he was no longer allowed to even make eye contact with strangers, let alone yell at them.

“Dean,” Castiel snapped, yanking on his leash. “Bend over and hold your ankles,” he ordered.

Dean’s face bloomed with a hot blush as he realized what he’d done and what would happen now. But he couldn’t do anything but obey. “Yes, Daddy,” He whimpered, bending over and gripping his own ankles. “I’m sorry, Daddy.”

Castiel let Dean hold that pose while he turned back to the other alpha. “Sorry about that, he’s just started his transition, he’s still got a long ways to go.”

“No worries,” the other alpha said, smiling easily. He seemed in no rush to leave, interested in watching Dean’s punishment.

Dean yelped when the first sharp smack of Castiel’s hand landed on his ass. It continued for ten strokes until his ass was a nice, burning red. He whimpered in relief when he was finally allowed to stand back up.

“I’m sorry, Daddy,” he said softly, eyes low. He was suddenly feeling very submissive, more so than usual.

“You’re forgiven,” Castiel said, smiling and pressing a kiss to Dean’s lips. “Now come on, we don’t want to miss your appointment.

* * *

The procedure was much easier than Dean had expected, and he recovered quickly. It felt a little weird at first, but he started to get used to it after a couple days.

It helped his recovery that Castiel very diligently applied all the creams and ointments required, so that by the time his stitches came out there was nothing left but a fading scar. Even that would eventually be gone.

“Your skin is so soft here,” Castiel said. He was holding Dean on his lap, the future omega’s legs open wide so that the alpha could touch as he wanted. His finger tips were currently stroking Dean’s castration scar, teasing the delicate skin.

Dean whimpered and blushed. “Thank you, Daddy,” he said, trying not to squirm. His daddy never missed a chance to remind Dean of his castration, it was a little embarrassing, but that was obviously the point.

All of this was definitely working. Day by day Dean was getting more and more comfortable with his submission. He could feel his body changing too, he was already losing muscle mass, and he could swear he’d even lost a little height. He wasn’t sure how that was possible. Maybe he was just holding himself differently. His cock was _definitely_ getting smaller, and Dean wasn’t thrilled about that, but it helped that his daddy seemed pleased by the change.

Dean wasn’t sure when he’d stopped thinking of Castiel as Cas and switched to just Daddy. It didn’t matter, Dean loved his daddy and wanted to please him, that was all that mattered.

“I think you’re healed up enough to start your spanking routine,” Castiel said, fingertips moving on to teasing Dean’s soft cock, making him whimper a little. “Do you remember what you need to do?”

Dean blushed deeply and nodded. “Yes, Daddy.” They’d talked about this before they started his change, maintenance spankings to help further his submission. To add a layer of humiliation it was Dean’s responsibility to ask for them, twice a day. He bit his lip, it was after dinner, he knew what Castiel wanted. “Daddy, may I please have my evening spanking?”

Castiel grinned. “Yes you may, my good little boy,” he said, finally pulling his hand away from Dean’s cock. “Get up and bend over my lap,” he ordered.

Dean shivered and felt the compulsion to follow the order, which he did. That was new, the internal instinct to do as he was told. Must be an omega thing.

Daddy’s hand landed on Dean’s ass with a sharp crack and he gasped at the mix of pain and pleasure. That was new too, Dean was starting to feel real pleasure when his alpha punished him. He jumped at the second smack, squirming on Castiel’s lap, his little cock trying to get hard.

“Hold still,” Castiel ordered, reaching around and pulling the plug from Dean’s ass and dropping it on the floor. Seed from his daddy’s earlier knot quickly started to escape and run down the inside of Dean’s legs.

Dean let out a yelp when the next smack landed right on his slick entrance, and then he moaned as pleasure flooded through him. The smacks continued to land, going back and forth from his round ass to his twitching hole. His mouth hung open as a mix of moans and whimpers escaped, his mind spinning from the overwhelming mix of pain and pleasure.

When Castiel was finally done he picked up the plug and shoved it back into Dean’s ass, making him cry out in surprise. He laid limply over his alpha’s lap, panting hard, sore and desperately wishing he was allowed to come from a spanking. But he wasn’t, and he knew it.

“Go kneel in the corner,” Castiel said, pulling Dean up. “I want to see that bright red ass on display, you’ll stay there until it fades.”

“Yes, Daddy,” Dean managed, stumbling over to the corner and dropping to his knees. He spread his knees a little so that his daddy could see the seed running down his legs and his puffy, red rim clamping down around the plug. He hoped it would inspire his daddy to fuck him later.

It was the only time he was allowed to come, and even then only if Daddy felt like allowing it.

* * *

Castiel loved to take Dean on walks, usually right after a knot when his seed was leaking out from around the plug, so that everyone would know. His daddy also liked to touch Dean a lot in public, especially when people were around.

Today they were walking through the nearby park, as usually Dean only wore his collar and leash, and his plug in his ass. He didn’t even mind being barefoot anymore, his feet had toughened up after a couple months without shoes. It definitely helped that they lived in a warm climate.

A tall alpha woman was walking towards them on the footpath, and Dean recognized her as their neighbor Erika before he dropped his eyes submissively to the ground.

“Hello Castiel!” she greeted them. “Looks like Dean is coming along so nicely, he’s even starting to smell a little like an omega, isn’t he? And look how cute and tiny his cock has gotten!”

“Thank you!,” Castiel said, reaching out to tease Dean’s little cock with his finger tip. “He can’t come at all anymore unless he has a knot in his ass. And only with permission of course. Isn’t that right, Dean?”

Dean’s face burned but he nodded, staying submissively still. “Yes, Daddy.” He didn’t even have a thought in his mind about objecting to the way he was being degraded.

“You sure get clever with that sharpie,” Erika said, reading all the words across Dean’s body.

They read _wannabe omega_ and _Daddy’s baby boy._ On his hip he had an arrow pointing to his little cock that said _omega clit_ and on his lower back an arrow pointed to his plugged hole and read _well used hole._

Castiel just laughed. “He loves it, don’t you little boy?”

Dean burned but he couldn’t help the way his cock jumped a little bit in response to the humiliation. “Yes, Daddy.”

Erika just grinned and shook her head. “I’m sure he’ll be a claimed omega any day now,” she said, giving them a little wave and continuing on her way.

Castiel turned to Dean and kissed his cheek. “My good baby boy,” he murmured, his hand reaching down to grip the plug and twist it, pressing it against Dean’s prostate.

Dean let out a moan, all thoughts of his humiliation flying out of his mind in the face of pleasure from his alpha. He just spread his legs a little wider to give him better access, letting his daddy have whatever he wanted. He’d never felt more relaxed, and in that moment it was like he could feel knots untying in his stomach as something finally let go.

Dean jumped when his daddy let out a very possessive growl and pressed his nose to Dean’s neck.

“You smell like an omega,” Castiel snarled, gripping Dean’s leash tightly and pulling the new omega’s body flush against his own, Dean’s back to his chest.

Dean whimpered and pressed back against his daddy, his alpha, wanting and needing unlike anything he’d ever felt before. He whined as his daddy’s hand came around behind him and pulled the plug from his ass, releasing the first gush of slick from Dean’s body.

He was a real omega. _Finally_.

Castiel growled and shoved Dean off the path and onto his hands and knees in the grass. “My omega!” He snarled, already fumbling with this fly, Dean’s leash still gripped in his hand.

Dean moaned and dropped his face to the ground, arching his back and spreading his legs, offering himself to be claimed by his mate. His whole body thrummed with desperate need, and Dean distantly recognized  that this must be his first heat, brought on hard by his transition.

“Daddy, please!” he begged, with no care for how many people in the park might be watching.

Castiel’s hard cock was suddenly there, pressing against Dean’s slick hole and then driving inside. His daddy immediately started thrusting fast and deep, and Dean moaned and gripped the grass between his fingers as he was fucked hard. He could feel the slick gushing out of his hole and running down the inside of his legs, mingling with Daddy’s seed from earlier that day.

It didn’t take long, Castiel’s instincts driving him to knot and claim Dean as quickly as possible. Dean howled as the knot filled him, and it felt better than it ever had before, and he had no idea how that was even possible. Castiel was pulling back on the leash, forcing Dean to bring his head up and arch his back.

“Come for me, little omega,” Castiel ordered, knot slamming into Dean as he came.

Dean cried out and came hard just as his alpha’s knot tied inside him and seed started to steadily fill him, and he let out a deep moan when he felt Castiel’s teeth sink into his neck, marking him as really and truly owned.

They finally collapsed to the grass, and Dean spared a moment to realize he was going to have to walk home with grass stains on his arms, knees, and face. But then he realized everyone in the neighborhood probably already heard his moans, so what did it matter?

“My omega,” Castiel growled, pressing his face to Dean’s neck. He was still fully clothed, and his shirt rustled against Dean’s back. His hips continued to gently grind against Dean as his knot continued to spill into him.

“Yours, Daddy,” Dean said with another moan, closing his eyes and leaning back into his daddy’s arms, happy to relax and enjoy his first knot as a true omega. He knew there would be many more to come.

* * *

Originally they hadn’t thought their arrangement would be permanent. They’d both agreed that after Dean was changed they wouldn’t have to do the humiliation and public nudity anymore.

But it turned out that Dean really liked having a daddy, and his daddy really liked having a good little boy. And they both really enjoyed the little games Castiel liked to play. So in the end, nothing changed after Dean’s transition.

Well, nothing except for the two growing pups in Dean’s belly. They were almost five months along, but with two of them Dean looked well over six months pregnant already. Dean looked down and rubbed his belly, smiling at the words from his last walk with his daddy. _Bred up bitch_ was written in an arch across his swollen belly in Castiel’s neat handwriting.

Castiel walked up behind Dean and wrapped his arms around the omega, bringing his hands to rest possessively on the swollen pup bump. “I’ve got plans for you,” he said, leaning in to kiss Dean’s neck. “I’m gonna take you for a walk and let you suck my knot under that big oak tree in the park. Would you like that, baby boy?”

Dean shivered, eager to do anything to please his mate. “Oh, yes Daddy!”

**Author's Note:**

> Thanks for reading! Comments are love. <3
> 
> Follow me on tumblr :) [omegadeanlovesalphacas.tumblr.com/mobilemenue](http://omegadeanlovesalphacas.tumblr.com/mobilemenu)


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